Reproductive Options

What is PGD?

PGT (Pre-implantation genetic testing) is available to couples that are at risk of having a child with a specific genetic or chromosome disorder. It prevents the birth of an affected child by testing an embryo before it is implanted in the uterus (womb).

Briefly, it involves the use of Assisted Reproductive Technology (ART), which in other circumstances is offered to couples with fertility problems. The aim is to obtain and fertilise a number of eggs. Once fertilised, the embryos develop for three days and then one cell is removed from each embryo. The genetic material (DNA or chromosomes) within each cell is then tested for the altered gene or chromosome abnormality. Up to two unaffected embryos are then transferred to the uterus with the hope that they will implant and form a pregnancy. If successful, a pregnancy should be unaffected. PGT is a lengthy and complex process. The stages of PGT treatment are described in a booklet written by  Guys and St Thomas hospital and can be found here.

Leukodystrophies approved for PGT:


Aicardi-Goutieres Syndrome;


Canavan Disease;


some types of GM2 gangliosidosis;

Krabbe Disease;

some types of Leighs Disease;

Metachromatic Leukodystrophy;

some types of Oculodentodigital Dysplasia;

Pelizaeus-Merzbacher Disease;

Peroxisome Biogenesis Disorders

This list is subject to change; to check the official list of conditions approved within the UK, go to Human Fertilisation and Embryology Authority.

For further information on how to be referred please visit Guys and St Thomas hospital.

For parents facing difficult decisions around pregnancy, the support organisation Antenatal Results and Choices (ARC) provides excellent information and resources.